So on ad infinitum;
which is very true, inasmuch as from the great humble-bee down to the tiniest corn-thrips—a mere speck of dust to the naked eye—all insects have their parasites, and generally their own special species of ichneumon, to prevent their over-increase and to preserve the due balance of nature. There is a species of longicorn beetle, found in Pennsylvania, which feeds upon the tender bark of young hickory shoots. When laying-time arrives, the female, having deposited her eggs in cavities perforated in the bark, carefully cuts a groove, about one-tenth of an inch wide and deep, round the shoot just below where her treasures lie. The object, or rather we suppose we ought to say the consequence, of this act is the withering and decay of the shoot, a provision for the sustenance of her young, which, when in their larval state, live upon dead wood! This remarkable insect is called the hickory girder from the above-mentioned habit, which, we think, is one of the most extraordinary instances of foresight, through a mere blind instinct, that have ever come under observation.
The gadfly (Œustrus equi), whose larvæ are the bots which inhabit the intestines of the horse, gains for her progeny that comfortable position by entrapping the animal itself into introducing her eggs within its stomach. For this purpose, she lays her eggs upon such portions of the horse’s body as he is in the habit of frequently licking, such as the knees, shoulders, &c. The unerring nature of her instinct is shown by the fact that she never chooses as a nidus any portion of the body which the horse is unable to reach with its tongue. Having thus been introduced into their natural feeding-grounds, the bots there pass their larval existence, until, it becoming time for them to assume the pupal form, they go forth with the animal’s dung to reach the earth, burrow into it, and therein pass the insects’ purgatory.
Again, one of the grain-moths (Gelechia cerealella) shows remarkable instinct in adapting itself to circumstances according to the time of year when it has to deposit its eggs. The first generation of these moths, emerging in May from pupæ which have lain in the granaries through the winter, lay their countless eggs upon the as yet ungathered corn, upon which their young play havoc until, having passed through the necessary stages, they come out in the autumn as the second generation amidst the now stored-up grain. Now, however, their instinct prompts them, not, like the first generation, to go forth to the fields to seek the proper nest and future nourishment of their young, but bids them deposit their eggs upon the store of wheat ready at hand. Thus, two following generations of the same insect are led by their instincts to different habits to suit the altered and, in the last case, unnatural position of their infants’ destined food-supply.
The interesting mason-wasp, having with great care and skill bored out a cylindrical hole in some sunny sandbank, deposits at the bottom of this refuge her eggs. Next, provident mother as she is, she seeks out about a dozen small caterpillars, always of the same species, and immures them alive in the pit, as food for her cruel children. In making her selection of grubs to be thus buried alive, she rejects any that may not have reached maturity; not, we imagine, upon the score of their not being so full-flavoured, but because, when not full grown, they require food to keep them alive; whereas, when of mature age, they will live a long time without nourishment, ready to turn to chrysalides when opportunity occurs.
These are but a few of the instances which might be adduced in illustration of this foresight in insects, which compensates for their not being allowed in person to superintend the welfare of their offspring. In many cases, it would be better for human progeny were their parents thus endowed with an unerring instinct, rather than with an uncertain will.
A BREAK-NECK VENTURE.
It is more than thirty years since my medico-military lines were cast in the little picturesque station of Badulla, the capital of Oovah, in the interior of Ceylon. This district was the centre of very considerable European enterprise in coffee-growing, and, both socially and commercially, was an important unit of the Kandian provinces; hence government, in addition to a small garrison of troops, had established in it a staff of its Civil servants, for the administration of fiscal and judicial affairs, and it is concerning one of these officials—the assistant district judge, as he was called—that my story is now to be told.
The judge was a young gentleman of good parts and attractive manners. He was a dead-shot, an excellent angler, a perfect rider, a very Dr Grace or Spofforth of a cricketer, and an intelligent, chatty, pleasant companion to boot. He had also a sure foot and a steady head. He could walk along the verge of a rocky precipice with a sheer descent of hundreds of feet as unconcernedly as many a man trudges over a turnpike road. Chaffingly, we were wont to tell him that he had entirely mistaken his vocation in life, and that instead of being ‘an upright judge,’ trying ‘niggers,’ he ought to have been another Blondin, trundling wheelbarrows on a rope stretched across Adam’s Bridge from Manaar to Ramisseram, and cooking a prawn curry in a stove when in the very middle of the Straits. However, even in the capacity of the aforesaid judge, this proclivity of being able to walk safely upon next to nothing once stood him in good need, as I myself witnessed.
One afternoon he came into my quarters holding in his hand a letter, which the post had just brought him. I ought perhaps to mention that thirty odd years ago there were neither railroads nor electric telegraphs in Ceylon, and that travelling was comparatively slow, and to some extent uncertain. In the case of our station, however, we had little to complain of. The postal authorities at Colombo forwarded our mail-bags to Kandy—the first seventy-two miles of the way—by a daily two-horsed coach; and from that city to their destination, ‘runners’ carried the letters. But these ‘runners’ now and again met with accidents of various sorts, such as being killed by elephants or tigers; and it so happened that something of the sort—I forget what—having occurred to detain my friend’s letter, it was older by more than twenty-four hours than it should have been, when he got it.